Method and apparatus for radio link synchronization and power control in CELL—FACH and idle mode

ABSTRACT

A method and apparatus for radio link synchronization and power control in CELL_FACH state and idle mode are disclosed. A wireless transmit/receive unit (WTRU) transmits a random access channel (RACH) preamble and receives an acquisition indicator acknowledging the RACH preamble via an acquisition indicator channel (AICH) and an index to an enhanced dedicated channel (E-DCH) resource. The WTRU determines a start of an E-DCH frame. An F-DPCH timing offset is defined with respect to one of the RACH access slot and an AICH access slot carrying the acquisition indicator. A relative F-DPCH timing offset may be signaled to the WTRU and the WTRU may determine a start of an E-DCH frame based on the relative F-DPCH timing offset and timing of an AICH access slot including the acquisition indicator. The WTRU may transmit a dedicated physical control channel (DPCCH) power control preamble before starting an E-DCH transmission.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/090,643 which issued on May 19, 2015 as U.S. Pat. No. 9,036,617,which is a continuation of U.S. patent application Ser. No. 12/346,617,filed Dec. 30, 2008, which issued on Dec. 24, 2013 as U.S. Pat. No.8,615,002, which claims the benefit of U.S. Provisional Application Ser.Nos. 61/025,695 filed Feb. 1, 2008 and 61/018,059 filed Dec. 31, 2007,the contents of which are hereby incorporated by reference herein.

BACKGROUND

The evolution of high speed packet access (HSPA) is being considered forhigher throughput and lower latencies. Due to the increase of dataservices, in particular internet services such as web browsing, wherehigh data rates are requested for short periods of time, the thirdgeneration partnership project (3GPP) Release 99 (R99) mechanism oftransitioning wireless transmit/receive units (WTRUs) in CELL_FACH toCELL_DCH requires significant network resources and adds latency to theservices. To support these types of services in CELL_FACH, it has beenproposed that the WTRUs are allowed to use the enhanced dedicatedchannel (E-DCH) with shared resources without transitioning to CELL_DCH,which is referred to as “enhanced random access channel (E-RACH) access”or “E-DCH in CELL_FACH state and Idle mode”.

An E-RACH access is a combination of a random access channel (RACH)preamble transmission phase and an E-DCH transmission phase. FIG. 1shows an E-RACH access procedure. The RACH preamble transmission phaseuses a subset of R99 RACH signatures that a Node B has designated orbroadcasted for use in E-RACH. The reception of a preamble by the Node Bis acknowledged in an acquisition indication channel (AICH), which alsoassigns a WTRU with an index for a shared E-DCH resource to use. Theshared E-DCH resources are pre-designated by the Node B for use in anE-RACH access in CELL_FACH. For all shared E-DCH resources, theparameters are provided to the WTRU during initial setup or broadcast toWTRUs in the cell by the Node B. Each E-DCH resource is associated withan index which is transmitted as part of the acknowledgement for theE-RACH access, or using some other signaling mechanism.

Once the WTRU receives the index value, all configuration parametersrelated to the assigned shared E-DCH resource are known and the WTRUdoes not need to communicate with the Node B in the same way as in R99.Indeed, in E-RACH, the E-DCH is used for the message transmissioninstead of the regular R99 10 or 20 ms physical random access channel(PRACH) message part.

The E-RACH access eliminates the overhead associated with theconventional CELL_FACH to CELL_DCH transition. The shared E-DCH resourceis released upon completion of data transfer and the WTRU remains inCELL_FACH so that other WTRUs could use the shared E-RACH resources.Thus, a significant reduction in transition latency is achieved and iteliminates transition back to CELL_FACH with re-initialization whenCELL_DCH is terminated. The WTRU may request permanent transition toCELL_DCH directly from E-RACH access.

The conventional RACH access starts with preamble transmission of onerandomly selected PRACH signature out of a set of up to 16 signatures,with a preconfigured initial power level. If no response is received onthe associated AICH from the Node B, the WTRU selects the next availableaccess slot, increases power by a predefined amount and transmits a newrandomly selected signature from the set of available signatures. If themaximum number of preamble transmissions is exceeded or negativeacknowledgement (NACK) is received, the WTRU exits the PRACH accessprocedure and reports it to a higher layer, (i.e. medium access control(MAC)).

If a positive acknowledgement (ACK) response is received from the NodeB, the WTRU transmits a RACH message three or four uplink access slotsafter the uplink access slot of the last transmitted RACH preamble. FIG.2 shows timing relationship between RACH access slots and AICH accessslots. The RACH access slot precedes the corresponding AICH access slotby τ_(p-α). For instance, if the WTRU transmits a preamble on PRACHaccess slot #2, the WTRU may get an ACK response on AICH access slot #2,and the WTRU may begin transmission of the RACH message on PRACH accessslot #5 or #6, depending on the WTRU capabilities.

3GPP Release 8 (R8) E-RACH access during CELL_FACH starts with RACHpreamble transmission followed by shared E-DCH transmission when anE-DCH resource is assigned by the Node B as shown in FIG. 1. A NACK orno response from the Node B requires the WTRU to transmit again in thenext available access slot until the maximum number of attempts has beenexhausted. The Node B responds to the RACH preamble via an AICH as inR99. The timing of the start of the E-DCH transmission has been agreedas a fixed time offset relative to the fractional dedicated physicalchannel (F-DPCH) frame timing (same as regular E-DCH). The F-DPCH timingoffset, expressed by the variable τ_(F-DPCH,p), is set by the networkand may be different for different F-DPCHs, but the offset from theP-CCPCH frame timing is always a multiple of 256 chips. FIG. 3 shows theradio frame timing and access slot timing of downlink physical channels.FIG. 4 shows the downlink and uplink timing relationship between primarycommon control physical channel (P-CCPCH), AICH, F-DPCH, dedicatedphysical control channel (DPCCH) and E-DCH.

One of the issues associated to the use of E-DCH in CELL_FACH state andIdle mode resides in determining the F-DPCH frame timing. In theconventional systems, the F-DPCH frame timing is signaled explicitly bythe network when the WTRU is transitioned to CELL_DCH. The F-DPCH framedictates the beginning of the DPCCH preamble transmission, whichessentially determines the start of the uplink scrambling code sequence.Since it is difficult to initialize the scrambling code in the middle ofa frame, it is typically necessary for the WTRU to start uplinktransmission after crossing the frame boundary at least once.

Fixing the F-DPCH frame timing to the P-CCPCH, as it is currently donein CELL_DCH, may cause difficulties with E-DCH in CELL_FACH. Indeed, itmay lead to a possibility of power control update being delayed by asmuch as a full frame (10 ms). To illustrate, consider an E-RACH preambletransmitted in an access slot near the end of an uplink E-DCH frame, aswould be defined by the E-DCH shared resource F-DPCH frame timing (withrespect to the fixed P-CCPCH). Assuming an ACK is transmitted over theAICH, this ACK response will be received at the end of the uplink E-DCHframe or at the beginning of the next uplink E-DCH frame so that theWTRU may not have an opportunity to transmit (due to the need toinitialize the scrambling code) until the beginning of the next E-DCHframe. This will result in a long delay before the power control loopcan be established, essentially making the first power control updatenearly a full frame, (i.e., 10 ms), after the last RACH preambletransmission. This may cause power control loop stabilization problem.It may also result in additional latency for sending the RACH messagepart. Thus, for a given F-DPCH offset relative to the P-CCPCH, someaccess slots will be more advantageous than others for E-RACH access,and some access slots may not be preferable due to power control updatelatency.

SUMMARY

A method and apparatus for radio link synchronization and power controlin CELL_FACH state and idle mode are disclosed. A WTRU transmits an RACHpreamble and receives an acquisition indicator acknowledging the RACHpreamble via an AICH and an index to an E-DCH resource. The WTRUdetermines a start of an E-DCH frame. An F-DPCH timing offset is definedwith respect to one of the RACH access slot and an AICH access slotcarrying the acquisition indicator. A relative F-DPCH timing offset maybe signaled to the WTRU and the WTRU may determine a start of an E-DCHframe based on the relative F-DPCH timing offset and timing of an AICHaccess slot including the acquisition indicator. The WTRU may transmit aDPCCH power control preamble before starting an E-DCH transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1 shows an E-RACH access procedure;

FIG. 2 shows timing relationship between RACH access slots and AICHaccess slots;

FIG. 3 shows the radio frame timing and access slot timing of downlinkphysical channels;

FIG. 4 shows the downlink and uplink timing relationship betweenP-CCPCH, AICH, F-DPCH, DPCCH and E-DCH;

FIG. 5 shows an example case with 60% of the access slots are assignedfor R99 RACH access and 40% of the access slots are assigned for R8E-RACH access;

FIG. 6 shows relative and absolute timing offset;

FIG. 7 shows an example scenario for E-DCH transmission;

FIG. 8 shows four radio slots of DPCCH preamble transmission beforeE-DCH transmission;

FIG. 9 shows transmission of DPCCH-only transmission after crossing theF-DPCH frame boundary; and

FIG. 10 is a block diagram of an example WTRU.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “WTRU” includes but is notlimited to a user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a computer, or any other type of user device capable ofoperating in a wireless environment. When referred to hereafter, theterminology “Node B” includes but is not limited to a base station, asite controller, an access point (AP), or any other type of interfacingdevice capable of operating in a wireless environment.

The embodiments are applicable to R8 and beyond of the 3GPP widebandcode division multiple access (WCMDA) standards where E-RACH is used toprovide access to shared E-DCH resources during CELL_FACH state or idlemode without a need for full scale switch over to CELL_DCH as inprevious releases. It should be noted that the embodiments disclosedherein may be extended to any wireless systems other than WCDMA or 3GPPR8.

In accordance with a first embodiment, the power level for E-DCHtransmission followed by successful RACH preamble transmission iscontrolled with P_(p-m) offset using an open loop power control schemesimilar to R99. The power offset P_(p-m) is measured in dB is an offsetbetween the power of the last successfully transmitted RACH preamble andthe control part of the random access message. The power offset P_(p-m)is modified based on the time to the next E-DCH frame boundary. Themeasured power level during RACH preamble transmission may be adjustedhigher when the E-DCH transmission slot is further away from the lastRACH preamble transmission. The adjustment function may be linear,parabolic or dB increments to account for the uncertainty.

In accordance with a second embodiment, the PRACH access slots arelimited so that the selected E-RACH preamble slot assures the E-DCHtransmission to be near the uplink frame boundary. The E-RACH preambletransmission may be restricted to E-DCH frame center. For example, forthe particular case of a zero F-DPCH offset, the PRACH access slots maybe limited to access slots 4, 5, 6, 11, 12, 13, and 14 as allowableslots for E-RACH preamble transmissions.

The E-RACH preamble transmission may be allocated per RACH sub-channelas specified in 3GPP TS 25.214 v7.5.0 and provided here in Table 1. ARACH sub-channel defines a sub-set of the total set of RACH accessslots. There are a total of 12 RACH sub-channels as shown in Table 1.Based on the uplink and downlink timing relationship and E-DCH frameboundary, appropriate row may be selected in Table 1 for the RACHpreamble transmission. The access slots may be limited based on thevalue of τ_(F-DPCH,p) since τ_(F-DPCH,p) may be used to calculate E-DCHframe boundary.

TABLE 1 SFN modulo 8 of corresponding P-CCPCH Sub-channel number frame 01 2 3 4 5 6 7 8 9 10 11 0 0 1 2 3 4 5 6 7 1 12 13 14 8 9 10 11 2 0 1 2 34 5 6 7 3 9 10 11 12 13 14 8 4 6 7 0 1 2 3 4 5 5 8 9 10 11 12 13 14 6 34 5 6 7 0 1 2 7 8 9 10 11 12 13 14

In accordance with a third embodiment, because certain access slots aremore favorable to R8 E-RACH access, given the F-DPCH time offset(τ_(F-DPCH,p)), a subset of access slots is allocated for R8 WTRUs andremaining slots are allocated for R99 WTRUs. For example, half theaccess slots that are favorable to R8 E-RACH access may be assigned toR8 WTRUs while the rest of access slots may be assigned to R99 WTRUs.

The access slot assignment may be dynamic. The access slots reserved forR99 and R8 E-RACH accesses may be configured by the network so that whenR99 WTRUs are prominent, more access slots may be assigned for R99 RACHaccess and when R8 WTRUs with E-RACH access capability become prominent,more access slots may be assigned for R8 E-RACH access. The exactdivision of access slots may be determined by a Node B or a radionetwork controller (RNC). FIG. 5 shows an example case with 60% of theaccess slots are assigned for R99 RACH access and 40% of the accessslots are assigned for R8 E-RACH access.

In accordance with a fourth embodiment, a second preamble may betransmitted to re-adjust the proper power level for shared E-DCHtransmission if it has been too long since the last RACH preambletransmission. In this case, higher number of RACH preamble transmissionsmay result since those WTRUs in unfavorable RACH access slots wouldrequire second preamble transmissions to re-adjust the power level ofshared E-DCH transmission.

In accordance with a fifth embodiment, the shared E-DCH transmissionpower level may be estimated based on CPICH measurement or any otherreference channel measurement at the time of the RACH preamble and/orshared E-DCH transmissions.

In accordance with a sixth embodiment, the timing of the F-DPCH frame isset in a way that results in a short delay between the last RACHpreamble transmission on the RACH access slot and its initial E-DCHtransmission. This delay should be short enough to ensure that thetransmission power level used for the last RACH preamble is still a goodstarting point for the E-DCH transmission, minimizing potential powersynchronization issues and excessive uplink interference.

Conventionally, the F-DPCH timing offset (τ_(F-DPCH,p)) is defined withrespect to the P-CCPCH frame boundary. In accordance with the sixthembodiment, the F-DPCH timing offset that is allocated to the WTRU isdefined with respect to either the start or end of the last RACHpreamble transmission or reception plus optionally an additional offset,or the start or end of the last AICH transmission or reception plusoptionally an additional offset. The F-DPCH timing offset may bepre-defined or signaled through higher layer signaling, (e.g., throughthe system information block (SIB)). Since the F-DPCH timing offset isrelative to the timing of the last RACH preamble transmission orreception or AICH transmission or reception, the issue of having apotentially large delay between this last RACH preamble transmission andthe E-DCH transmission disappears.

It is advantageous to have resources defined with different F-DPCHtiming offsets as it allows multiple WTRUs to share the same F-DPCHchannelization code. Alternatively, instead of defining a resource interms of an F-DPCH timing offset, the F-DPCH timing offset relative toPRACH access slot transmission may be fixed to a pre-defined value forall resources, but resources for WTRUs may be defined in terms of adifferent F-DPCH slot format. Using a different F-DPCH slot format fordifferent resources allows the Node B to allocate the same F-DPCHchannelization code to multiple WTRUs with full flexibility even if theF-DPCH timing offset is pre-determined.

Alternatively, the network may broadcast an F-DPCH “relative” timingoffset, (relative to the RACH transmission or reception, or AICHtransmission or reception). This would allow multiple WTRUs tosimultaneously share the same F-DPCH channelization code, while at thesame time provide flexibility in selecting an F-DPCH “absolute” timingoffset with respect to the P-CCPCH that minimizes the delay between thelast RACH preamble transmission and the start of the E-DCH transmission.The network may broadcast the F-DPCH “relative” timing offset associatedwith each E-DCH resource via a system information block(s) (SIB). For asystem with N radio slots per frame and K WTRUs sharing the same F-DPCH,each resource may be assigned a unique F-DPCH “relative” timing offsetR_off=0 . . . K−1. The WTRU and the network may then have flexibility toselect a slot number (S_num=1 . . . N) that would minimize the delay.Rules are specified for the selection of the slot number to guaranteeagreement between the WTRU and the network, (e.g., the slot number S_nummay be fixed in the standards). With the F-DPCH relative timing offsetassociated with the resource and the slot number pre-configured orselected by the WTRU and the Node B, the F-DPCH “absolute” timing offsetmay be computed by (S_num−1)×K+R_off.

FIG. 6 shows relative and absolute timing offset in an example casewhere N=15 and K=10. FIG. 7 shows an example scenario of E-DCHtransmission. In FIG. 7, a successful RACH preamble has been transmittedin PRACH access slot 5, and the network responds with an ACK in AICHaccess slot 5. If E-DCH resources are available, they may be assigned tothe WTRU. This resource assignment is associated with an F-DPCH“relative” timing offset. The WTRU and the network determine to beginE-DCH transmission on slot 14 based on a preconfigured rule. Selectionof slot 14 may be based on a configured τ_(p-m) or some otherstandardized or network configured delay T, which may be broadcast, forexample, through SIB.

A DPCCH power control preamble, (i.e., DPCCH-only transmission withoutE-DCH transmission), comprising a number of DPCCH slots may betransmitted for several radio slots before the first E-DCH transmissionto help with uplink synchronization and stabilization of the powercontrol loop. FIG. 8 shows four radio slots of DPCCH preambletransmission before E-DCH transmission. In previous releases of the 3GPPstandards, the duration of the DPCCH preamble associated tosynchronization procedure A is defined in terms of number of radioframes. In accordance with this embodiment, the DPCCH preamble durationand start and stop time may be defined in terms of radio slots. Theduration of the DPCCH preamble may depend on the time difference betweenthe last uplink RACH preamble transmission and the start of the DPCCHpreamble. In this way, as the time difference gets larger the preambletransmission gets longer to stabilize the power control loop. Theparameters for selection of the preamble duration and preamble starttime may be signaled by a higher layer, or may be pre-configured and/orimplicit.

Optionally, the initial DPCCH preamble power level may be adjusted in asimilar manner to E-DCH power transmission power offset in accordancewith the first embodiment. The initial DPCCH preamble power level may beadjusted based on the time difference between the last RACH preambletransmission to the time where uplink transmission starts (DPCCH orE-DCH transmission). This allows a protection against time variations inthe channels that might potentially make the initial transmission fail.The parameters to select the amount of power offset may be signaled by ahigher layer, or may be pre-configured and/or implicit.

The transmission of a DPCCH-only preamble may lead to difficultiesassociated to the start of the uplink scrambling code. The uplinkscrambling code is a pseudo-random sequence with a period of one radioframe, (i.e., 10 ms). The start of the uplink scrambling is synchronizedwith the beginning of the E-DCH radio frame. Thus, in the case where theWTRU starts transmission of the DPCCH preamble before the start of theuplink radio frame, the WTRU and the Node B need to know where to startthe scrambling sequence, which is a difficult task due to the very ownnature of scrambling sequence generation.

In order to solve this problem, a common uplink scrambling code may betemporarily used for the duration of the DPCCH preamble and possibly thefirst few E-DCH transmission time intervals (TTIs) in the case of theE-DCH with 2 ms TTI. This common uplink scrambling may bepre-configured, signaled via a higher layer, or implicit. For instance,the common uplink scrambling code may be the same scrambling code as theone used by the WTRU for the last access preamble on the RACH. Since theWTRU knows the common uplink scrambling code in advance, the WTRU maystart uplink transmission anywhere in the radio frame, essentiallyallowing early transmission of the DPCCH preamble. In addition, the useof the common scrambling code for DPCCH preamble allows for quickdetection and synchronization of DPCCH preamble transmission. In suchcase, the DPCCH preamble duration would essentially depend on the timedifference between the last RACH preamble transmission and the start ofthe E-DCH transmission. Optionally, an additional DPCCH preamble periodmay be defined after the start of the F-DPCH frame so that the Node Bhas sufficient time to synchronize with the new scrambling code. Thisperiod may be pre-defined or signaled by the network.

Alternatively, the alignment of the F-DPCH frame for the E-DCHtransmission in CELL_FACH may be made such that the DPCCH preamble(using the allocated uplink scrambling code) always starts aftercrossing at least one F-DPCH frame boundary after the WTRU gets itsE-DCH resource assignment on the AICH/E-AICH. This may be achieved, forinstance, by selecting the F-DPCH time offset based on the RACH accessslot or the AICH access slot. FIG. 9 shows transmission of DPCCH-onlytransmission after crossing the F-DPCH frame boundary. In FIG. 9, theE-DCH transmission is off for the first N transmission time interval(s)(TTI(s)) and DPCCH-only transmission is transmitted for the first NTTI(s).

The conventional F-DPCH frame offset from the P-CCPCH frame timing,τ_(F-DPCH,p), is a multiple of 256 chips. τ_(F-DPCH,p) may be expressedas a sum of an integer number of radio slots, (i.e., multiple of 2,560chips from the beginning of the P-CCPCH frame), and a radio slotfractional offset expressed as a multiple of 256 chips:τ_(F-DPCH,p) =L×2560+k′×256,  Equation (1)where L=0, 1, . . . , 14 and k′=0, 1, . . . , 9. The radio slotfractional offset allows using the same F-DPCH channelization code forseveral WTRUs (assuming the same F-DPCH slot format).

To make sure that the F-DPCH frame boundary arrives shortly after theE-DCH resource allocation on the AICH or E-AICH, the network maybroadcast as part of the E-DCH shared resource only the part of thetiming offset that determines when the transmit power control (TPC)commands are sent within the radio slot for a given F-DPCHchannelization code, or equivalently the radio slot fractional offset(assuming a fixed F-DPCH slot format) or equivalently a combination ofradio slot fractional offset and F-DPCH slot format. This informationmay be represented by k′ in Equation (1). The part of the timing offsetexpressed in terms of integer number of radio slots (e.g., expressed byL in Equation (1)), includes an offset L′ defined relative to the lastRACH preamble sent by the WTRU (or equivalently an offset definedrelative to the transmission of the AICH since there is a fixed timingrelationship between the RACH and the AICH). This offset L′ may bepre-configured by the standards or signaled by a higher layer, (e.g., aspart of the SIBs). This allows the F-DPCH frame offset to be defined asclose as possible to the start of the uplink transmission, while leavingall the F-DPCH channelization code allocation flexibility at the Node B.The resulting absolute F-DPCH frame offset (L) relative to the P-CCPCHcan then be expressed as the sum of (1) the offset from the P-CCPCHframe determined by the timing of the last transmitted RACH access slot(or the AICH access slot), (i.e., the number of RACH or AICH accessslots from the P-CCPCH frame before transmission of the RACH preamble orreception of the AICH), (2) the offset (L′) relative to that last RACHpreamble (or the received AICH), and (3) the signaled offset (k′) withinthe radio slot (in multiple of 256 chips). Note that the F-DPCH frameoffset is always positive and relative to the closest P-CCPCH frame.Thus, truncation may be applied if necessary.

An additional benefit of broadcasting the relative timing offset withinthe radio slot instead of the absolute timing offset with respect to theP-CCPCH for each common E-DCH resource is that the former requires muchless information than the latter. Indeed, signaling one of 10 offsetsper radio slot requires 4 bits while signaling one of 150 offsets (10offsets per slot, 15 slots per radio frame) would require 8 bits. Thismay represent a significant advantage given that this information isbroadcast on the SIBs for each of the common E-DCH resource.

FIG. 10 is a block diagram of an example WTRU 1000. The WTRU 1000includes a transmit/receive unit 1002, a controlling unit 1004, and ameasurement unit 1006. The transmit/receive unit 1002 is configured totransmit an RACH preamble in a randomly selected RACH access slot,receive an ACK or NACK indicator via an AICH in response to the RACHpreamble, and transmit an E-RACH message via an E-DCH. The controller1004 is configured to perform control functions for radio linksynchronization and power control in accordance with the first throughseventh embodiments disclosed above including adjustment of a poweroffset between a transmit power of the acknowledged RACH preamble and atransmit power of a control part of the E-RACH message based on a timeto a next E-DCH frame boundary since transmission of the acknowledgedRACH preamble, selection of the RACH access slot in a way assuring thatthe E-DCH transmission is near an uplink frame boundary, initiating atransmission of another RACH preamble to determine a transmit power foran E-RACH message if a time elapsed since the acknowledged RACH preambletransmission is longer than a predetermined threshold, determining atransmit power for the E-RACH message transmission based on the CPICHmeasurement, determining an F-DPCH timing offset with respect to one ofthe acknowledged RACH preamble transmission and the AICH reception inresponse to the RACH preamble, controlling transmission of the DPCCHpower control preamble, and the like. The measurement unit 906 isconfigured to perform measurements, such as CPICH measurements.

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

What is claimed is:
 1. A method for radio link synchronization and powercontrol in CELL_FACH state, the method comprising: transmitting a randomaccess channel (RACH) preamble; receiving an acquisition indicator inresponse to the RACH preamble and obtaining an index to an enhanceddedicated channel (E-DCH) resource; receiving a fractional dedicatedphysical channel (F-DPCH) according to a F-DPCH reception starting time,wherein the F-DPCH reception starting time is based on a relative F-DPCHtiming offset parameter and timing of an acquisition indicator channel(AICH) access slot including the acquisition indicator; transmitting apower control preamble; and transmitting a dedicated physical controlchannel (DPCCH) according to a DPCCH transmission starting time, whereinthe DPCCH transmission starting time and the F-DPCH reception startingtime are offset by a predetermined offset.
 2. The method of claim 1wherein the relative F-DPCH timing offset parameter is acquired prior totransmitting the RACH preamble.
 3. The method of claim 1 wherein theF-DPCH reception starting time is calculated by calculating a firstoffset calculated by adding the relative F-DPCH timing offset parametermultiplied by 256 chips to a predetermined number of chips, and addingthe first offset to a beginning of the RICH access slot including theacquisition indicator, and the DPCCH transmission starting time iscalculated by adding the predetermined offset to the F-DPCH receptionstarting time.
 4. The method of claim 1 wherein the relative F-DPCHtiming offset parameter is received via a system information block(SIB).
 5. The method of claim 1 wherein the acquisition indicatorindicates an index to an enhanced dedicated channel (E-DCH) resource. 6.The method of claim 1, further comprising: transmitting a RACH messagevia an enhanced dedicated channel (E-DCH).
 7. The method of claim 1wherein the RACH preamble is transmitted utilizing a randomly selectedsignature.
 8. The method of claim 1 wherein the RACH preamble istransmitted in a randomly selected access slot.
 9. A wirelesstransmit/receive unit (WTRU) for radio link synchronization and powercontrol in CELL_FACH state, the WTRU comprising: a transmit/receive unitconfigured to transmit a random access channel (RACH) preamble, receivean acquisition indicator in response to the RACH preamble, and obtain anindex to an enhanced dedicated channel (E-DCH) resource, receive afractional dedicated physical channel (F-DPCH), transmit a power controlpreamble, and transmit a dedicated physical control channel (DPCCH)according to a DPCCH transmission starting time; and a controllerconfigured to control reception of the F-DPCH according to a F-DPCHreception starting time, wherein the F-DPCH reception starting time isbased on a relative F-DPCH timing offset parameter and timing of anacquisition indicator channel (AICH) access slot including theacquisition indicator; wherein the DPCCH transmission starting time andthe F-DPCH reception starting time are offset by a predetermined offset.10. The WTRU of claim 9 wherein the relative F-DPCH timing offsetparameter is acquired prior to transmitting the RACH preamble.
 11. TheWTRU of claim 9 wherein the F-DPCH reception starting time is calculatedby calculating a first offset calculated by adding the relative F-DPCHtiming offset parameter multiplied by 256 chips to a predeterminednumber of chips, and adding the first offset to the beginning of theRICH access slot including the acquisition indicator, and the DPCCHtransmission starting time is calculated by adding the predeterminedoffset to the F-DPCH reception starting time.
 12. The WTRU of claim 9wherein the relative F-DPCH timing offset parameter is received via asystem information block (SIB).
 13. The WTRU of claim 9 wherein theacquisition indicator indicates an index to an enhanced dedicatedchannel (E-DCH) resource.
 14. The WTRU of claim 9 wherein thetransmit/receive unit is further configured to transmit a RACH messagevia an enhanced dedicated channel (E-DCH).
 15. The WTRU of claim 9wherein the RACH preamble is transmitted utilizing a randomly selectedsignature.
 16. The WTRU of claim 9 wherein the RACH preamble istransmitted in a randomly selected access slot.